• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.525-526
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• 2011

전력계통에서 발생하는 고장 중에는 고장 후의 결과만을 가지고는 어떻게 고장이 초기에 발생하여 진전되었는지를 추정하기가 어려운 고장이 간혹 발생한다. 본 고장 분석사례는 보호계전기의 동작사항과 고장기록장치의 파형을 이용하여 송전선로에서 고저항 지락에 의한 최초의 고장이 발생 할 수 있는 가능성과, 그 고장으로 인한 파급 고장 사례를 예시하였다. 과도현상 분석 프로그램인 EMTP (Electro-Magnetic Transient Program)를 이용하여 고장 사례를 재현하여 Fault Recorder 기록과의 유사성을 확인하였다.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.17 no.3
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• pp.47-52
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• 2008

The force transducer in the acceleration plant due to dynamic fracture is calibrated by dynamically using the stress pulses from a longitudinal bar. The bar is supported by two strings attached to the ceiling. The bar velocities before and after impact are measured and a full bridge at bar and transducer is formed by the four strain gauges. A transient recorder is used to store the stress pulse signals of force transducer and bar. For the first test series, three point bend test specimens can be chosen by means of test rig design and the inspection as sample experiment in this presented paper is sufficient for proving with the numerical simulation of the specimen model.

• 전기의세계
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• v.11
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• pp.1-7
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• 1963

직류분권 전동기에 있어서 정상운전시에 계자회로를 개방하면 회전자의 속도가 매우 상승하는 경향이 있다. 여기에서는 이러한 이상현상 자체를 수학적으로 해석해서 개방후의 회전자의 속도변화와 전기자전류의 변화를 시간의 함수로써 구하였다. 그리고 회전자의 속도 및 전기자전류, 잔류자기와 회전자 최종속도와의 관계, 부하 torque를 생각했을 경우의 회전자속도강하조건, 및 speed-torque curve도 구해보았다. Speed-torque curve의 경우에는 수학적으로는 복잡함으로 간단히 하기 위하여 과도기간을 편의상 subtransient와 transient의 두가지 period로 나눈 다음 물리적 현상을 고려하여 sub-transient를 무시해서 생각하였다. 본 실험에서 detector로는 Diehl tachometer-generator를, tachometer입력으로는 Hewlett-Packard사제 Model 200CD형 oscillator에 의한 20cps signal을 사용하였다. 그리고 회전 속도와 전기자전류를 Duel Channel Sanborn-150 recorder로 기록하였다.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.7 no.3
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• pp.465-472
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• 1997

An extension of new test methods for surfaces with an apparatus based on photon-induced desorption and ionisation in the electric field, is constructed and tested, It also investigates how to show the efficiency of the arrangement adsorbates $H_2$ and He on W(110). The field emitter temperature was 80 K. The wavelength of light used was 193 nm with field strengths between 10 and 50 V/nm. Many ion fragments($CO^+, He^+, H_2^^+, H_2O^+, W^{3+}\; and\; W^{2+}$) were produced by an electronic stimulation of the adsorbate with the help of a photon energy of 6.4 eV at He and $H_2$/W(110). A transient recorder enables the registration of the entire mass spectrum.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.527-528
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• 2011

송전선로에서 발생하는 고장의 대부분은 낙뢰에 의한 상-대지간 섬락이나 외물접촉, 혹은 애자련의 오손에 의한 절연파괴 등이 대부분이다. 그리고 대분의 고장은 큰 고장전류를 흘리게 되어 보호계전기가 동작하여 고장구간을 신속하게 분리하게 된다. 그러나, 본 고장사례는 매우 희귀한 고장 사례로서, 고저항 아크 지락에 의하여 발생하는 과도회복전압(TRV: Transient Recovery Voltage)이 애자련에 섬락을 일으킨 경우이다. 본 연구에서는 EMTP (Electro-Magnetic Transient Program)를 이용하여 고저항 지락시 아크의 단속에 의하여 과도회복전압이 발생할 가능성이 있음을 보였으며, 고장기록장치(Fault Recorder)에 나타난 파형 기록과의 유사성을 확인하였다. 또한, 고저항 지락에 의하여 직류분이 초기에 방전됨으로써 고장전류 파형에 직류분 오프셋이 나타나지 않게 됨을 밝혔다.

• Journal of the Korean Magnetics Society
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• v.5 no.5
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• pp.395-398
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• 1995

For the core loss measurement under arbitrary waveform of magnetic induction, we have constructed a single sheet core loss measuring system which consists of yoke apparatus for single sheet of $10\;cm{\times}10\;cm$, arvitrary waveform synthesizer, B-feedback system, and two channel transient recorder. Using the constructed measuring system, we can measure core loss including higher harmonics up to 2 kHz. Core loss of non-oreinted electrical steel was increased exponentially when higher harmonic frequency was increased or amplitude of harmonic induction was increased.

• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.169-171
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• 2005

This paper presents a two-terminal approach for fault location estimation and for faults recognition. The proposed algorithm is also based on the synchronized phasors measured from the synchronized PMUs installed at two-terminals of the transmission lines. Also the arc voltage wave shape is modeled numerically on the basis of a great number of arc voltage records obtained by transient recorder. From the calculated arc voltage amplitude it can make a decision whether the permanent or transient fault. The results of the proposed algorithm testing through computer simulation are given.

• Journal of Electrical Engineering and Technology
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• v.1 no.1
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• pp.35-41
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• 2006

This paper presents a new numerical algorithm for fault location estimation and for faults recognition based on the synchronized phasors. The proposed algorithm is based on the synchronized phasor measured from the synchronized PMUs installed at two-terminals of the transmission lines. In order to discriminate the fault type, the arc voltage wave shape is modeled numerically on the basis of a great number of arc voltage records obtained by transient recorder. From the calculated arc voltage amplitude it can make a decision whether the fault is permanent or transient. The results of the proposed algorithm testing through computer simulation are given.

• Proceedings of the KIEE Conference
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• 2006.11a
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• pp.354-356
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• 2006

This paper presents a new one-terminal numerical algorithm for fault location estimation and for faults recognition. The proposed algorithm are derived for the case of most frequent single-phase line to ground fault in the time domain. The arc voltage wave shape is modeled numerically on the basis of a great number of arc voltage records obtained by transient recorder. From the calculated arc voltage amplitude it can make a decision whether the fault is permanent of transient. In this paper the algorithm uses a very short data window and enables fast fault detection and classification for real-time transmission line protection. To test the validity of the proposed algorithm the Electro-Magnetic Transient Program(EMTP/ATP) is used.

• Proceedings of the KIEE Conference
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• 2005.11b
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• pp.283-285
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• 2005

This paper presents a new two-terminal numerical algorithm for fault location estimation and for faults recognition using the synchronized phasor in time-domain. The proposed algorithm is also based on the synchronized voltage and current phasor measured from the PMUs(Phasor Measurement Units) installed at both ends of the transmission lines. Also the arc voltage wave shape is modeled numerically on the basis of a great number of arc voltage records obtained by transient recorder. From the calculated arc voltage amplitude it can make a decision whether the fault is permanent or transient. In this paper the algorithm is given and estimated using DFT(Discrete Fourier Transform) and the LES(Least Error Squares Method). The algorithm uses a very short data window and enables fast fault detection and classification for real-time transmission line protection. To test the validity of the proposed algorithm, the Electro-Magnetic Transient Program(EMTP/ATP) and MATLAB is used.